SDR

After seeing Chris G0DWV’s talk I thought I’d have a go at building one of the Softrock SDR kits. I bought the 80/40m version because W+S didn’t have the 20m one in stock.

I was a bit worried about soldering the surface mount components but these were relatively straightforward to do.

First component done! (1p for scale)

All of the SMDs done. Note the wonky components!

Construction took about 4 hours or so, the most tricky parts being the winding of the third inductor and the 20 mins spent trying to extract a resistor I’d put in the wrong place from the plate through PCB.

Done!

If you are building a softrock you may want some PCB pins because they aren’t included and I immediately encountered problems when trying to wire up the board. It is a shame that these weren’t included in the kit

Does it work?

Yes! I’m amazed!

The PC was an old 1GHz laptop with only a 44khz soundcard

Here is 40m viewed using the Rocky software

Zoomed into a station

Tuning certainly seems a bit weird compared to using a normal radio. Here is a wav file to prove that it works.

I’ve installed PowerSDR and got it running with the Softrock on a 2GHz Vaio laptop. To do this, install the original PowerSDR and then download the SoftRock version available here.

Here it is in action listening to Alex, Yo9HP

The PowerSDR interface

Initial impressions of PowerSDR are that it has some nice filtering but tuning is a pain.

Excellent CW filtering

That said, the 50Hz filtering on CW has to be heard. The above image shows this – the CW sig being listened to is the one with the slightly wider, but thin, green line. The osc frequency/4 (?) signal can be seen on the right (or ground loop).

Update

Recently I’ve been setting up a new PC for my station. I’ve found that Rocky SDR software can lock up on my desktop and one of my laptops, which is a shame because I prefer it to PowerSDR.